Renal outcomes and survival in amyloidosis associated with familial Mediterranean fever: A longitudinal study

Abstract

Objectives

Long-term outcomes of Familial Mediterranean fever (FMF)-associated amyloidosis (FMF-amyloidosis) have been rarely evaluated. This study aimed to investigate renal and overall survival in patients with FMF-amyloidosis and define the factors affecting outcomes.

Methods

We retrospectively analyzed patients with FMF-amyloidosis treated between 2000 and 2022. The primary outcome was the rate of end-stage renal disease or death during the study period. Patients not achieving this outcome served as references to identify factors affecting the outcome.

Results

The study included 61 patients with FMF-amyloidosis, of whom 82% attained the primary outcome within a mean of 10.8 ± 9.6 years from the diagnosis of amyloid nephropathy. Lower estimated glomerular filtration rate (eGFR) and increased concomitant medication usage at the time of amyloidosis diagnosis were significant outcome determinants. Maximally selected rank statistics followed by survival analysis determined that an optimal eGFR cutoff <67 mL/min/1.73 m² at amyloidosis diagnosis was significantly associated with a shorter time to endpoint, with a 10-year kidney or overall survival of 17% versus 59% below or above this cutoff, respectively. Kaplan–Meier analysis revealed that treatment with interleukin-1 (IL-1) blockers, administered to 13 timely relevant patients, had no impact on outcomes.

Conclusions

FMF-amyloidosis generally has poor long-term prognosis, significantly influenced by the amyloid burden at diagnosis. IL-1 blocker efficacy in altering these outcomes remains uncertain owing to the small sample size.